1. Field of the Invention
The present invention relates to a movie projection system.
2. Description of the Related Art
In recent years, many video contents have been produced in a digital form, and it has become popular to use digital video data instead of analog films in screening movies in movie theaters or the like using movie projection systems. However, use of digital video data has a problem that digital video data can be easily copied or tampered with, and data acquired or copied in an authorized manner can be used to play back a movie or the like with high quality similar to that of the original data. Besides, recent widely-used broadband environments allow large-size data to be easily distributed, and, in fact, there is actually an environment that allows data to be distributed in an authorized manner using P2P (Peer to Peer) or similar techniques. If digital video data is stolen directly from a movie projection system, an incomparably great loss can occur.
However, currently available movie projection systems do not necessarily have high resistance to stealing of digital video data. A typical movie projection system includes, in a case, a storage device adapted to store digital video data and a video server adapted to read digital video data from the storage device and play back a content according to the digital video data. In many cases, to prevent digital video data from being easily read out in an unauthorized manner, the storage device and the video server have an encryption capability. However, even in such a movie projection system having an encryption capability, a transmission channel between the storage device and the video server does not necessarily have high resistance to tampering.
One technique for solving the above problem is to limit access to the inside of the case of the movie projection system. For example, a maintenance door of a case is configured to prevent an unauthorized opening, or the operation of the movie projection system is stopped when an unauthorized opening is detected. More specifically, a switch for detecting opening of a door is disposed on the door. If the door is opened in an authorized manner, the switch on the door turns on, and a signal may be supplied from the switch to notify a manager or an operator of the movie projection system of the occurrence of tampering.
Further related information may be found, for example, in Japanese Unexamined Patent Application Publication No. 5-34818.